Janne Karhunen wrote:
> Hi,
>
> So effectively, it makes me sleep better. With it:
> - I can rely on clients identifying the server correctly,
> - I'm not exposing out anything that is not needed,
> - Can tell by the address what this traffic is,
> - Can be sure that packets are sent out via right interface
>
> It might be even better if it would exit if -n is used when
> no such interface is actually available. As I did it, it still
> gambles here just as before.
>
>   

After browsing thru "statd -n" flow, it is still not clear what will 
happen if there are more than 2 interfaces used to export NFS shares ? 

Using "statd -H", together with patches described in:
https://www.redhat.com/archives/cluster-devel/2007-April/msg00028.html ,

our cluster failover (with 4 IP interfaces per server) seemed to run 
well without troubles. Note that 2/3 of the patch in 4-3 can be removed 
*now* since it deals with moving server address from network header into 
lockd internal structures - another similar patch (by Frank van 
Maarseveen) was accepted into mainline kernel after our patch that has 
the required functionality:
http://lkml.org/lkml/2007/7/10/553 .

So the following is our (-H) flow:
* Server dispatches statd with "-N" option that has a user mode script
   (sample program fotest.c enclosed). It is expected the user mode script
   could structure its nlm directory accordingly.
* Upon failover, the take-over server notifies clients with:
   "/usr/sbin/sm-notify -f -v floating_ip_address -P an_sm_directory"

The advantages of "-H" approach over "-n" are (I think ?):
* It can handle multiple NFS export network interfaces.
* It knows which clients coming from which interfaces to allow selective 
grace period for each interface.

In many ways, I would think "-n" should be obsolete ?

-- Wendy